Can Start node hidden field values be retrieved in onContinuePostLogin?

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Can Start node hidden field values be retrieved in onContinuePostLogin?

I’m building a custom consent screen using Auth0 Forms and a React app rendered via api.prompt.render() in a PostLogin Action.

I need to pass two values back to onContinuePostLogin after the user interacts with my React UI:

  • dma_accepted (true/false)
  • dma_consent_type (single/continuous)

What I’ve tried:

  1. Start node hidden fields — defined dma_accepted and dma_consent_type as hidden fields in the Start node, then tried setting them via document.querySelector('[name="dma_accepted"]') before submit. The query always returns null — no DOM element is rendered for Start node fields.

  2. context.form.setValue() + goForward() — setValue silently fails and goForward() hangs indefinitely on a pending WebSocket (wss://relay-dev.account.booking.com:3000/ws).

  3. POST to /continue — returns 400 Bad Request when posting custom fields directly.

  4. sessionStorage — client-side only, never reaches the Action.

What works (partially):
Adding Text Input controls directly in the Step, then using document.querySelector('[name="dma_accepted"]').value = 'true' before clicking the Continue button — this successfully passes values to event.prompt.fields in onContinuePostLogin. This mirrors the solution described in this thread.

My question:
Is there any supported way to pass values set programmatically (from a custom React app) back to onContinuePostLogin using Start node hidden fields — without needing to add visible/hidden Text Input controls in the Step?

Or is adding Step-level Text Input fields the only supported mechanism for writing data back to event.prompt.fields?

Any guidance appreciated. Thanks!

3

Hi @kathan.shanmugapriya

Welcome to the Auth0 Community!

To directly answer your question: No, you cannot use Start node hidden fields to pass data back to onContinuePostLogin . Adding Step-level Text Input controls (and hiding them from the user) is the only officially supported mechanism for writing custom programmatic data back to event.prompt.fields .

Your partially working solution (using document.querySelector on a Step-level input) is exactly the correct architectural approach for custom UI integrations within Auth0 Forms.

If you have any other questions, let me know!

Kind Regards,
Nik